KR20120111996A - Solution film forming method - Google Patents

Abstract

PURPOSE: A method for preparing a film is provided to manufacture a film with excellent processability and reworkability. CONSTITUTION: A method for preparing: a film comprises a flexible membrane(32) by flowing a dope on a support; a step of obtaining a wet film(16) by detaching the flexible membrane from the support in state the solvent is remaining; a step of maintaining a temperature of a flexible membrane to be not lower than gelling temperature by -3 °C; a step of drying the flexible film to solidifying the flexible membrane by a level enabling the detached wet film to be returned; and a step of obtaining a film(23) by drying the wet film. [Reference numerals] (11) Cellulose acylate; (12) Solvent; (13) Dope; (18) First tenter; (19) Second tenter; (34) Temperature controller; (37) Ventilator; (38) Controller

Description

Solution film formation method {SOLUTION FILM FORMING METHOD}

The present invention relates to a solution film forming method for producing a cellulose acylate film.

A cellulose acylate film is cut | disconnected to the dimension according to a use, and is used. Although cutting may consist only of a cellulose acylate film before combining with another member, it may be made with the member after combining with another member. As an example of the latter, a polarizing plate may be manufactured. A cellulose acylate film is used as a protective film which protects a polarizing film, and when manufacturing a polarizing plate, it cuts after bonding a polarizing film and a cellulose acylate film. Moreover, also when changing one of a pair of protective film arrange | positioned at both surfaces of a polarizing film into an optical compensation film (including a phase difference film), it is the same. Thus, the optical compensation film may be used as a protective film.

When cut | disconnecting the film of the multilayer structure to which the polarizing film and the protective film were bonded to the objective dimension in order to set it as a polarizing plate, a cutting blade is pressed and cut | disconnected from one film surface with respect to a multilayer structure film. Thus, when a multilayer structure film is cut | disconnected, a crack may arise in the inside of a protective film from the cut surface formed by cutting | disconnection. The protection film which a crack generate | occur | produces in this way by cutting is evaluated that processability is bad, and the commodity value becomes remarkably low also about the polarizing plate obtained.

Moreover, when manufacturing a liquid crystal display, a polarizing plate is stuck to a glass substrate. In the case of such bonding, when the bonding state does not become an intended state, what is called a rework which peels a polarizing plate once from a glass substrate and bonds again is performed. Among these rework, a part of the protective film of a polarizing plate may remain on a glass substrate at the time of peeling peeled from a glass substrate. Thus, the protection film which the whole did not peel off and a part remained on the glass substrate is evaluated that reworkability is bad, and it is not preferable.

As a manufacturing method of the cellulose acylate film used for optical uses, such as said display apparatus, there exists a solution film forming method. The solution film forming method is a manufacturing method in which a dope in which a polymer is dissolved in a solvent is cast on a support to form a cast film, the cast film is hardened and peeled off, and the peeled cast film, that is, the wet film, is dried to form a polymer film. As a support body which casts dope, a drum or a belt is used. The drum rotates in the circumferential direction with the rotation axis at the center of the circular cross section as the center of rotation, and the dope is flexible on the circumferential surface. The belt is circumferentially wound in the longitudinal direction over the circumferential surfaces of at least two rollers, and dope is cast on one of the belt surfaces. Although the size of a drum is large, the diameter of a cross section circular shape will be about 3.5 m from the manufacturing limit, and the circumferential length of the circumferential surface in which a casting film is formed stays about 3.5 (unit; m). On the other hand, a belt can be manufactured also in length of 100 m or more. For this reason, by using a belt, the distance (henceforth a flexible film conveyance distance) from peeling after forming a flexible film to peeling can be made longer than a drum. The solution film is largely classified into a dry gelation method and a cooling gelation method by the method of hardening the cast film.

The dry gelation method is a method of drying a cast film to a desired dry level, and gelling and hardening a cast film by this drying. That is, a casting film is dried and hardened to the extent that the wet film after peeling becomes conveyable. It is common to perform drying by blowing dry air into a casting film. In order to further promote this drying, the drying film is heated to warm air, or the casting film is heated by heating the support. In order to harden a casting | flow_spread film | membrane by drying, since it requires longer time than by the following cooling gelation system, it is customary to use a belt instead of a drum as a support body.

On the other hand, a cooling gelation method is a system which gelatinizes until it hardens to a conveyance even if it peels in a state in which the solvent residual rate is very high by actively cooling a casting film, and peels. This system can harden a cast film in a shorter time than a dry gelation system, so a drum may be sufficient as a support body.

As described above, in either case of the dry gelation method or the cooling gelation method, the cast film gels and hardens.

When comparing the dry gelation method and the cooling gelation method described above, the latter can be peeled off from the support while the solvent residual rate is high, and thus, the latter is remarkably superior in terms of production efficiency. However, the cellulose acylate film obtained by the cooling gelation method is inferior to the cellulose acylate film obtained by the dry gelation method from the viewpoint of the above processability and reworkability.

Many proposals are made about the solution film forming method using a dry gelation method, and the solution film forming method using a cooling gelation method, respectively. For example, as a solution film forming method using a dry gelling method, in the method of JP-A-2000-239403, the temperature of the support is in the range of 1 ° C or more and 80 ° C or less, and at the peeling position at which the flexible film is peeled off from the support. , Spray the gas stream. According to this method, it is said that the film which has a desired retardation can be manufactured efficiently.

Moreover, as described in Unexamined-Japanese-Patent No. 2006-306059, the method of gelatinizing a cast film is also proposed by performing both drying and cooling. In JP 2006-306059 A, the surface temperature of the belt as the support is set to -20 to 40 ° C. In JP 2006-306059 A, a belt is wound around one roller, and casting and peeling are performed on one roller. A blower is provided to face the belt from the one roller toward the other roller, and the drying wind is sent from the blower. A cooler is provided so as to face the belt that faces the peeling position from the other roller, and blows cooling air from the cooler to cool the cast film. Thus, in JP 2006-306059 A, the flexible film on the belt is dried in an upstream region in the conveying path and cooled immediately before peeling. According to this method, the film excellent in the optical characteristic can be manufactured efficiently.

However, even if the methods of JP-A-2000-239403 and JP-A-2006-306059 are applied, workability and reworkability cannot be reliably improved. Specifically, according to the method of JP-A-2000-239403, the processing aptitude and the reworkability may be relatively good, but in many cases, it is very bad. It does not definitely improve sex. Moreover, also about Unexamined-Japanese-Patent No. 2006-06059 method, processing aptitude and reworkability differ according to the film obtained, and it is hard to say that Unexamined-Japanese-Patent No. 2006-306059 method contributes to such an improvement.

Therefore, an object of this invention is to provide the solution film forming method which improves the workability and rework property of a film.

The solution film forming method of the present invention includes a flexible film forming step, a peeling step, a temperature support step, a flexible film drying step, and a wet film drying step. A casting film formation step forms a casting film by casting dope continuously on a support body. In the said dope, cellulose acylate is melt | dissolved in the solvent. A peeling step makes it the wet film by peeling the said flexible film from the said support body in the state which the said solvent remains. The temperature support step maintains the temperature of the flexible film until the peeling time point so as not to be lower than {(gel point TG of the dope) -3} ° C. The casting film drying step advances the drying of the casting film so that the casting film is hardened to such an extent that the peeled wet film can be conveyed. In the wet film drying step, the wet film is dried to form a film.

It is preferable to advance the drying of the said flexible membrane by adjusting the temperature of the said flexible membrane by controlling the temperature of the said support body, and sending a gas to the said flexible membrane.

It is preferable to maintain the temperature of the said flexible film to the time of peeling so that it may not become higher than {(gel point (TG) of the said dope) +3} degreeC.

It is preferable that the solution film forming method of this invention further comprises a conveyance path control step. The conveyance path control step makes the pressure of the second space upstream from the roller smaller than the pressure of the first space so that the conveying path of the wet film facing the roller is convex toward the second space side. The roller is provided on the side opposite to the support with respect to the conveying path of the wet film. The said roller is arrange | positioned so that a longitudinal direction may correspond to the width direction of the flexible surface of the said support body. The flexible film is peeled off by winding the wet film on the circumferential surface of the roller and conveying the wet film. The said 1st space is a space on one film surface peeled from the said support body of the said wet film. The second space is a space on the other film surface.

It is preferable to suck the gas of the said 2nd space upstream from the said roller by the suction apparatus which sucks gas, and to depressurize the said 2nd space between the said roller and the peeling position from which the said flexible film peels from the said support body. Do.

It is preferable that the said suction device is provided with the chamber which distinguish | separates the said 2nd space to be decompressed from an external space, and controls the path | route of conveyance of the said wet film toward the roller by adjusting the pressure in the said chamber. .

It is preferable to cast the said dope in the range whose viscosity is 7 Pa * s or more and 9 Pa * s or less to the said support body.

It is preferable to control the said viscosity by adjusting the temperature of the said dope.

It is preferable to calculate | require the said viscosity based on the pressure loss of the said dope in the said casting die.

According to the solution film-forming method of this invention, the film excellent in workability and rework property can be manufactured.

The above objects and advantages will be readily understood by those skilled in the art by reading the detailed description of the preferred embodiments with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram of the solution film forming installation which implemented this invention.
2 is a graph showing the relationship between the processing aptitude and the degree of orientation of the film.
3 is a graph showing the relationship between the degree of orientation and the temperature of the drum.
4 is a graph illustrating a method for obtaining a gel point.
5 is a partial cross-sectional side view showing the outline of FIG.
6 is a plan view illustrating an outline of.
7 is a partial cross-sectional view showing an outline of the flexible chamber.
8 is a graph showing the relationship between the viscosity of the dope and the temperature.

The solution film forming equipment 10 of FIG. 1 includes a wet film forming apparatus 17, a first tenter 18, a second tenter 19, a roller drying apparatus 22, and a winding device 24. Have The wet film forming apparatus 17 forms the wet film 16 from the dope 13 in which the cellulose acylate 11 is dissolved in the solvent 12. The 1st tenter 18 advances drying of the wet film 16 until it becomes a fixed solvent residual ratio, supporting and conveying each side part of the formed wet film 16 by a support means (not shown). . The second tenter 19 supports the side of the wet film 16 by supporting means (not shown), further drying the wet film 16 while applying the tension in the width direction to the wet film 16 as appropriate. Proceed. The roller drying apparatus 22 further advances the drying of the wet film 16 to the film 23 while conveying the wet film 16 having passed through the second tenter 19 to the roller 21. The winding device 24 winds up the dry film 23 in roll shape. In addition, the solution film-forming installation 10 is wet film 16 in each conveyance path between the 2nd tenter 19 and the roller drying apparatus 22, and between the roller drying apparatus 22 and the winding apparatus 24. FIG. ) And a slit device (not shown) for cutting each side end portion of the film 23, but not shown.

The wet film forming apparatus 17 includes a drum 29 as a support. The drum 29 has a rotating shaft 29b at the center of the circular cross section, and the rotating shaft 29b is rotated in the circumferential direction by driving means (not shown). As a result, the drum 29 rotates in the circumferential direction. By this rotation, the circumferential surface 29a becomes an endless flexible surface to which the dope 13 is flexible.

The drive means of the drum 29 has a controller (not shown), which controls the drive means such that the drum 29 rotates at a desired speed.

Above the drum 29, the casting die 31 which flows out the dope 13 is provided. The outlet port (not shown) of the casting die 31 which the dope 13 flows out is a slit shape extended in the longitudinal direction of the rotating shaft 29b. The flexible die 31 is disposed so that the outlet port faces the circumferential surface 29a of the drum 29. The dope 13 is cast on the drum 29 by continuously flowing the dope 13 from the casting die 31 to the rotating drum 29. By this casting, the casting film 32 is formed on the peripheral surface 29a which is the casting surface of the drum 29.

Regarding the dope 13 from the casting die 31 to the drum 29, a decompression chamber 44 (see FIG. 7) is provided upstream in the rotational direction of the drum 29, but is shown in FIG. 1. Omit. The decompression chamber 44 sucks the atmosphere of the upstream area | region of the dope 13 which flowed out, and depressurizes the said area | region.

A plurality of rollers 48 are provided in the movement between the drum 29 of the wet film forming apparatus 17 and the first tenter 18. The cast film 32 is hardened on the drum 29 to such an extent that conveyance by these rollers 48 is possible, and then the cast film 32 is peeled off from the drum 29 in the state containing the solvent.

The drum 29 has a temperature controller 34 that controls the temperature of the circumferential surface 29a. By controlling the temperature of the circumferential surface 29a by the temperature controller 34, the temperature of the flexible film 32 in contact with the circumferential surface 29a is controlled.

The wet film forming apparatus 17 has an air supply section 35 for sending gas to the cast film 32. The air supply part 35 includes the duct 36, the blower 37, and the controller 38. The duct 36 has a duct main body 36a and the some nozzle 36b. The duct main body 36a has a shape along the circumferential surface 29a of the drum 29 so as to cover the flexible film 32 passing therethrough, and is provided to face the circumferential surface 29a of the drum 29. The nozzle 36b protrudes and is provided in the opposing surface which opposes the drum 29 of the duct main body 36a. Each nozzle 36b is elongate in the width direction of the drum 29 corresponding to the longitudinal direction of the rotating shaft 29b, ie, in the width direction of the cast film 32. The plurality of nozzles 36b are formed so as to be arranged in the circumferential direction of the drum. A slit (not shown) is formed at the tip of the nozzle 36b facing the circumferential surface 29a of the drum 29. This slit is an opening extended in the width direction of the drum 29. Each slit flows out the gas supplied to the duct main body 36a.

The blower 37 supplies gas to the duct main body 36a. The controller 38 controls the temperature, humidity, and flow rate of the gas sent from the blower 37 to the duct 36. This control adjusts the temperature, humidity, flow rate and flow rate of the gas from the nozzle 36b. For example, the gas of the blower 37 is heated by the controller 38, and the drying of the cast film 32 is advanced by spraying the heated gas on the cast film 32 as warm air. In addition, by cooling the gas of the blower 37 by the controller 38 and spraying the cooled gas to the casting film 32 as cold air, drying of the casting film 32 can be advanced.

The duct 36 may be replaced with another blowing means. As another blowing means, for example, there are a plurality of blowing nozzles (not shown) in which an opening is formed at the tip, and the tip is directed toward the drum 29. In this case, a plurality of blow nozzles may be connected to the blower 37, and the gas guided from the blower 37 may be blown out from the openings of the respective tips.

In addition, the wet film forming apparatus 17 includes a casting chamber (casing) 45 that covers the casting die 31, the drum 29, the ducts 36, and the 41. The blower 37, the controller 38, and the temperature controller 34 are preferably disposed outside the flexible chamber 45. The flexible chamber 45 includes an air supply / exhaust unit 88 (see FIG. 7), and the air supply / exhaust unit 88 supplies an air supply unit 91 (see FIG. 7) for sending gas therein, and the gas inside. It has an exhaust part 92 (refer FIG. 7) to discharge. The supply / exhaust unit 88 controls the temperature, humidity, and solvent gas concentration in the inside of the flexible chamber 45 in a predetermined range, respectively. Although drying of the flexible film 32 advances to some extent also by this control, since it cannot be said that it is enough, it is preferable to use the air supply part 35. FIG. In addition, the solvent gas means that the solvent 12 evaporated and became gas.

As the temperature of the drum 29 is set slightly higher, drying of the casting film 32 proceeds. Moreover, depending on the kind of the solvent 12, it is easy to evaporate, and drying of the casting film 32 may be easy to advance. However, there is a limit to the amount of the solvent 12 to evaporate. Therefore, when evaporating more solvent, the air supply part 35 accelerates drying.

Although the influence of the gas by the air supply part 35 does not have any influence on the temperature of the flexible film 32, the influence of the temperature of the circumferential surface 29a of the drum 29 which contact | connects is very large. In addition, since the flexible film 32 is thin, when formed, the temperature of the flexible film 32 becomes substantially the same as the temperature of the circumferential surface 29a of the drum 29, and at the peeling position PP (refer FIG. 5) at the same time. Until this, the temperature of the circumferential surface 29a of the drum 29 is maintained. That is, the temperature of the casting film 32 from the casting position PC to the peeling position PP is maintained at the same temperature as the circumferential surface 29a of the drum 29. For this reason, the temperature of the flexible film 32 may not be detected, and the set temperature of the peripheral surface 29a of the drum 29 may be regarded as the temperature of the flexible film 32. Therefore, the temperature control means of the flexible film 32 is the drum 29 as a support body. The set temperature of the drum 29 is mentioned later using another figure.

At the time of peeling, the wet film 16 is supported by a roller for peeling (hereinafter referred to as a peeling roller) 33, and the peeling position PP at which the cast film 32 is peeled from the drum 29 (see FIG. 5). Keep constant).

Upstream of the peeling roller 33, it is preferable to provide 41 which controls the path | route of the wet film 16 toward the peeling roller 33. As shown in FIG.

The method of peeling the flexible film 32 from the drum 29 is mentioned later using another figure.

The wet film 16 formed by peeling is conveyed by the roller 48 and guided to the 1st tenter 18. As shown in FIG. In the 1st tenter 18, the side end part of the wet film 16 is supported by a support means (not shown), and the wet film 16 is dried, conveying by this support means. The supporting means is a plurality of pins (not shown). The wet film 16 is supported by passing a pin through the side end portion of the wet film 16. The pin of each side end part moves to a conveyance direction, applying a tension moderately with respect to the width direction of the wet film 16. As shown in FIG. The tension is set based on the optical performance (for example, retardation) of the film 23 to be manufactured. For example, in the case where the width of the wet film 16 is widened at a predetermined magnification in order to express the desired optical performance on the film 23, the wet film 16 is in the width direction so as to have a predetermined magnification. To give tension.

The second tenter 19 downstream of the first tenter 18 is also provided with a plurality of supporting means for supporting each side end of the wet film 16. This support means is a clip which grips the side end part of the wet film 16. As shown in FIG. The plurality of clips impart a predetermined tension to the width direction of the wet film 16 at a predetermined timing. The tension given in the 2nd tenter 19 is also set based on the optical performance (for example, retardation) of the film 23 to be manufactured.

The 1st, 2nd tenters 18 and 19 all have the chamber (not shown) which surrounds a conveyance path. Ducts (not shown) are provided inside the respective chambers of the first and second tenters 18 and 19, respectively. In these ducts (not shown), a plurality of air supply nozzles (not shown) and suction nozzles (not shown) are formed to face the conveying path of the wet film 16, respectively. By the delivery of the dry gas from the air supply nozzle and the suction of the gas from the suction nozzle, the interior of the chambers of the first and second tenters 18 and 19 is maintained at a constant humidity and solvent gas concentration. By passing the inside of each chamber of the 1st, 2nd tenters 18 and 19, drying of the wet film 16 is advanced. In the 1st tenter 18, the wet film 16 is dried to the extent to be gripped by the clip of the 2nd tenter 19. FIG. On the other hand, in the second tenter 19, the degree of drying to be reached is determined in consideration of the timing of tension provision in the width direction.

The wet film 16 which passed through the 2nd tenter 19 is a slit apparatus (not shown), and each side end part with a support mark by a support means is cut continuously with a cutting blade, and is removed. The center part between one side end part and the other side end part is sent to the roller drying apparatus 22.

When the wet film 16 is sent to the roller drying apparatus 22, it is supported by the circumferential surface of the some roller 21 arrange | positioned side by side in the conveyance direction. Among these rollers 21, there is a driving roller that rotates in the circumferential direction and is conveyed by the rotation of the driving roller.

The roller drying apparatus 22 is provided with the duct (not shown) which flows out the dried gas, and has a chamber (not shown) which distinguishes the space where dry gas is conveyed from the outside. The plurality of rollers 21 are housed in this chamber. In the chamber of the roller drying apparatus 22, a gas introduction port (not shown) and an exhaust port (not shown) are formed. By supplying the drying gas from the duct and exhausting from the exhaust port, the inside of the chamber of the roller drying apparatus 22 is maintained at a constant humidity and solvent gas concentration. By passing the inside of the chamber of this roller drying apparatus 22, the wet film 16 is dried and it becomes the film 23. FIG.

The film 23 dried by the roller drying apparatus 22 is a slit apparatus (not shown), and each side end part is cut continuously with a cutting blade and removed. The center part between one side end part and the other side end part is sent to the winding-up apparatus 24, and is wound up in roll shape.

In FIG. 1, the case where the drum 29 is used as a support body is shown. However, the support may be an annular belt (not shown) wound around the peripheral surface of a plurality of rollers (not shown). When the belt is used as the support, at least one of the plurality of rollers on which the belt is wound is a driving roller that rotates in the circumferential direction. By rotation of this drive roller, a belt is conveyed in a longitudinal direction and it circulates continuously.

In the case where the belt is used as the support, the roller on which the belt is wound may be adjusted to adjust the temperature of the circumferential surface, and the temperature of the belt may be controlled by this roller. As described above, the present invention does not limit the support to the drum 29.

The casting time from the flexible position PC at which the dope 13 contacts the peripheral surface 29a of the drum 29 and starts to form the flexible film 32 to reach the peeling position PP is the drum. Depends on the rotational speed of (29). For example, the greater the rotational speed of the drum 29, the shorter the casting time. Moreover, since the drum 29 has a limit in the size which can be manufactured, the flexible film conveyance distance from a flexible position to a peeling position is extremely short compared with a belt. Therefore, when using the drum 29 as a support body, it is preferable to gelatinize by setting the temperature of the circumferential surface 29a which is a casting surface low, and cooling the casting film 32 actively. However, even if the flexible film 32 is cooled, the lower the temperature is, the better. The lower limit of the temperature and the setting method will be described later.

On the other hand, when using a belt as a support body, the casting film conveyance distance from the casting position PC to the peeling position PP depends on the length of a belt. Therefore, for example, when using a short belt of less than 10 m as a support, gelation may be performed by setting the belt to a low temperature and actively cooling the cast membrane as in the case of using the drum 29. However, as described above, even if the flexible film 32 is cooled, the lower the temperature, the better. The lower limit of the temperature and the setting method will be described later.

On the other hand, when using a long belt of 10 m or more as a support, for example, the belt may be set at a high temperature, and drying of the cast film may be performed to gel. When the temperature of the belt is set high in order to advance the drying, the flexible membrane is not actively and intentionally cooled because the main purpose is to increase the drying rate of the flexible membrane (amount of solvent evaporating from the flexible membrane per unit time). . However, when manufacturing a cellulose acylate film, the casting film becomes low in temperature compared with the dope 13 at the time of flowing out from the casting die 31 by the component of dope 13, etc. In this sense, even in the case of gelation by drying, as a result, the cast film has a lower temperature than the dope 13 at the time of outflow from the cast die 31.

The setting method of the temperature of the circumferential surface 29a of the drum 29 is demonstrated below using FIGS. The processability and the degree of orientation of the film are related to each other. First, the relationship between processability and the orientation degree of a film is calculated | required. In addition, the orientation degree here is the degree of the orientation in the direction along a film surface. This relationship may be represented, for example, as a graph as shown in FIG. In FIG. 2, the vertical axis | shaft is workability, and workability is so favorable that it goes downward. The horizontal axis is an orientation degree, and the orientation degree is high toward the right side.

In FIG. 2, the curve A shown by a broken line and the curve B shown by a solid line are graphs regarding the films obtained from the dope 13 of the prescription which differs mutually on the same manufacturing conditions, respectively. Curve A and curve B differ from each other in the relationship between orientation and workability. In this way, the relationship between the orientation and the processing aptitude depends on the prescription of the dope 13. In either of curves (A) and (B), the degree of orientation is higher as the workability is poor. Therefore, in order to raise workability, what is necessary is just to manufacture a film so that orientation degree may become lower.

In the case of gelation by cooling, the cast film 32 is peeled from the drum 29 in a state where the solvent residual ratio is very high as compared with the case of gelation by drying. For this reason, when peeling the casting film 32 from the drum 29, there exists a tendency for the wet film 16 to expand | stretch larger in the conveyance direction of the wet film 16 corresponding to the peeling direction. Therefore, this elongation becomes one of the causes, and the film 23 obtained by gelation by cooling tends to show a high degree of orientation rather than the film 23 obtained by gelation by drying. However, the relationship between the workability and the degree of orientation is common, and the higher the degree of orientation, the worse the workability. Moreover, the relationship between workability and orientation degree has a correlation with the prescription of dope 13, regardless of what gels with cooling and drying. For this reason, the relationship between workability and orientation is sufficient for every prescription of dope 13.

Here, let MT be the target processing ability level, and the orientation degree corresponding to this target level MT is calculated | required. Since the obtained orientation degree is an orientation degree corresponding to the target level MT of a workability, this is called a target orientation degree PT hereafter. In order to achieve the target level MT of workability, the film 23 is manufactured so as to have the orientation degree of the objective orientation degree PT or less. Thus, the objective value of the orientation degree of the film 23 which should be manufactured is set from the level of the target processability. Let the target orientation degree in curve (A) be (PTa), and the target orientation degree in curve (B) be (PTb).

In addition, the same graph can be obtained even if the vertical axis is set to rework instead of workability. Therefore, you may replace the objective level PT of workability with the objective level of rework property.

Moreover, the relationship between the temperature of the drum 29 and the orientation degree of the film obtained is calculated | required. This relationship may be shown, for example as a graph like FIG. In FIG. 3, the vertical axis | shaft is an orientation degree, and an orientation degree is low, so that it goes downward. The horizontal axis is the temperature of the support, the higher the temperature toward the right. In FIG. 3, the case where dope 13 which manufactures the film of the curve A of FIG. 2 is used is shown. However, the same tendency is obtained also when the dope 13 which manufactures the film of the curve B of FIG. 2 is used. That is, the relationship between the temperature of the drum 29 and the orientation degree of the film obtained becomes the same tendency regardless of the prescription of the dope 13 to be used.

As shown in FIG. 3, the higher the temperature of the drum 29 is, the lower the degree of orientation of the film obtained. Therefore, in order to make orientation degree lower, the temperature of the drum 29 may be made higher, the temperature of the casting film 32 may be maintained at a higher temperature, and the film 23 may be manufactured. Moreover, about the film obtained from the dope 13 of a certain prescription, as shown in FIG. 2, processing aptitude and an orientation degree correspond one-to-one, and as shown in FIG. 3, the orientation degree and the temperature of the drum 29 are shown. Has a one-to-one correspondence. Therefore, with respect to the film obtained from the dope 13 of a certain prescription, process suitability and the temperature of the drum 29 become one-to-one correspondence.

Here, the temperature of the circumferential surface 29a of the drum 29 corresponding to the target orientation degree PT is obtained. The temperature of the peripheral surface 29a of this drum 29 is set to T1. The higher the temperature of the circumferential surface 29a of the drum 29, the lower the degree of orientation of the film obtained, so that the temperature of the circumferential surface 29a of the drum 29 is expressed from the viewpoint of expressing the degree of orientation below the target orientation degree PT. What is necessary is just T1 or more. Therefore, T1 becomes a lower limit of the temperature which should be set of the circumferential surface 29a of the drum 29. Therefore, the temperature T1 of the circumferential surface 29a of the drum 29 determined as described above is referred to as the minimum set temperature. In addition, the code | symbol T2 is attached | subjected to FIG. 3 at the upper limit of the set temperature of the circumferential surface 29a of the drum 29 (henceforth a maximum set temperature), and this maximum set temperature is mentioned later.

In this way, the lower limit of the set temperature of the circumferential surface 29a of the drum 29 is set from the target level of workability through the degree of orientation. In addition, as mentioned above, the temperature of the flexible film 32 and the temperature of the circumferential surface 29a of the drum 29 can be regarded as the same. Therefore, in order to manufacture the film 23 whose workability satisfies the target level MT, in order to keep the temperature of the flexible film 32 not lower than T1 until the time of peeling (until the peeling position PP is reached). The temperature of the peripheral surface 29a of the drum 29 is made the minimum set temperature T1 or more. Thereby, the film in which workability satisfies the target level MT is manufactured.

If the workability is the target level MT, the rework property is the target level. Moreover, in the said example, although the lower limit of the setting temperature of the peripheral surface 29a of the drum 29 is set from the objective level of workability through an orientation degree, you may set from the objective level of rework property through the orientation degree. In this case, if the reworkability satisfies the target level, the machining aptitude also satisfies the target level.

In addition, the gelation point TG with respect to the dope 13 of a certain prescription can be calculated | required by the following method. This method finds the gel point from the storage modulus G 'and the loss modulus G', and is already widely used as a method for obtaining the gel point. In FIG. 4, the vertical axis indicated by the solid line on the left is the storage modulus (G ′), and the vertical axis indicated by the broken line on the right is the loss modulus (G ′). It shows that either vertical axis is a higher value as it goes upward. The horizontal axis is the temperature of the dope, the higher the temperature toward the right. The method for determining the storage modulus G 'and the loss modulus G' is not particularly limited, and a known method may be used. In addition, in this embodiment, the storage elastic modulus G 'and the loss elastic modulus G' are calculated | required by the viscoelasticity measuring apparatus (model: MCR-300) by Physica.

The curve 1 shown by the solid line in FIG. 4 is a graph which shows the relationship between the storage elastic modulus G 'and the temperature of the dope 13, The curve 2 shown by the broken line shows the loss modulus G' and the dope It is a graph which shows the relationship with the temperature of (13). The storage modulus G 'and the loss modulus G' both decrease as the temperature of the dope 13 increases. As described above, the storage modulus G 'and the loss modulus G' of the dope 13 each have a dependency on temperature, that is, a temperature dependency. However, the storage modulus G 'and the loss modulus G' differ from each other on the temperature of the dope 13, and in a polymer solution such as the dope 13, there is an intersection when both are graphed. do. The temperature indicating this intersection is the gelation point TG of the dope 13. As described above, the gelation point TG of the dope 13 is obtained from the intersection point when the storage modulus G 'and the loss modulus G' are graphed.

When the relationship between the minimum set temperature T1 calculated | required previously and the gel point TG (unit; degreeC) calculated | required by FIG. 2 and FIG. 3 etc. is obtained, (TG))-3} ° C ((T1) = ((TG) -3) ° C). As described above, since the lowest set temperature T1 coincides with the gel point TG for the dope of a certain prescription, the gel point TG is determined to obtain the drum 29 from the processing aptitude and the reworkability through the orientation. It is not necessary to determine the lower limit of the set temperature of the circumferential surface 29a. That is, the set temperature of the circumferential surface 29a of the drum 29 may be {(gel point TG) -3} ° C. or more from the viewpoint of improving workability and reworkability.

In addition, the relationship that the minimum set temperature T1 coincides with a temperature lower by 3 ° C. than the gel point TG is obtained in the present for the film 23 having a thickness of 40 μm and for example 60 μm thicker than 40 μm. Based on the objective level (MP) of workability and the objective level of reworkability. In the future, there is a strong possibility that the level of the workability obtained will be higher than the current level. In that case, what is necessary is just to calculate | require the temperature of the support body corresponding to the level of workability calculated | required similarly through an orientation degree. When the level of the workability determined is increased, the difference between the gelation point TG (= TG-T1) and the minimum set temperature (T1) of the support body similarly determined through the degree of orientation becomes smaller than 3 ° C. Therefore, the set temperature of the peripheral surface 29a of the drum 29 becomes temperature higher than {(gel point TG) -3} degreeC. Moreover, although the thickness of the thinnest thing currently calculated | required is 40 micrometers, there exists a possibility that the thickness of the film calculated | required may become thinner in the future. As the thickness of the film becomes thinner, fine crystallization of cellulose acylate molecules tends to proceed, and according to this tendency, processing aptitude may be lowered. For this reason, when manufacturing the film 23 thinner than 40 micrometers, and processing aptitude becomes low, the set temperature of the peripheral surface 29a of the drum 29 is more than {(gel point TG) -3} degreeC. It is good to make it high temperature.

From the viewpoint of the above setting method of minimum set temperature T1 and improvement of workability and reworkability, the temperature of the peripheral surface 29a of the drum 29 is made into {(gel point TG) -3} degreeC or more. It is applicable to any solution film formation which gelatinizes and peels a casting film | membrane. Moreover, setting the circumferential surface 29a of the drum 29 and the belt temperature by setting the minimum set temperature T1 as described above, and making these temperatures at a constant temperature or higher certainly improves workability and reworkability. Let's do it. Moreover, according to such a method, since it does not affect the optical performance (for example, retardation) made into the objective of the film 23 to be manufactured, in the 1st tenter 18 and the 2nd tenter 19, You may perform extending | stretching, drying in the roller drying apparatus 22, etc. without changing the conditions set so far.

However, in the case of gelation by cooling, the gelation is less likely to proceed as the temperature of the peripheral surface 29a of the drum 29 is set higher, and the flexible film 32 is formed even when the peeling position PP is reached. There arises a problem such as not hardening enough to convey. Therefore, in the conventional cooling gelation method, in order to make production more efficient, it is common to set the temperature of a support body at especially low temperature among the well-known temperature range of a support body, and to cool a flexible film | membrane. For example, in the cooling gelation method in which cellulose acylate is cellulose triacetate (TAC), when the drum 29 having a flexible film conveying distance is about 10 m, the temperature of the peripheral surface 29a is cooled to about -10 ° C. do. However, the lower the temperature of the drum 29, the higher the orientation and the worsening of workability and reworkability. In the present invention, the drum 29 is active as in the case of gelation by cooling. Even if it cools by the said temperature, it does not make temperature lower than said minimum set temperature T1.

Therefore, in the case where the drum 29 is actively cooled and gelation is performed by cooling, in order to harden the flexible film 32 to the extent that the peeled wet film 16 can be conveyed, that is, the self-supporting property is expressed, The casting film 32 is dried. That is, in order to express self-supportability, the casting film 32 is dried in addition to cooling. As described above, in the present invention, when actively cooling the drum 29 including the viewpoint of manufacturing efficiency, the gelling effect due to cooling is lower than that in the conventional cooling gelation method by the lowest set temperature T1. As it loses, it replenishes the gelling effect upon drying. In other words, the drying step of the casting film 32 is a step of gelling replenishment that replenishes the cooling gelling effect (gelling action) and solidifies the casting film. Moreover, even when the drum 29 as a support body replaces a long belt like the flexible film conveyance distance, for example 100 m, when the belt is actively cooled, at a temperature of {(gel point TG) -3} ° C. or more Gelling does not proceed to the extent that the cast film 32 exhibits self-supportability. For this reason, the drying process for supplementing the gelling effect by cooling is performed. In addition, in this embodiment, drying which supplements a gelling effect is performed with respect to the casting | flow_spread film 32 cooled. That is, cooling and drying are performed in parallel.

However, if the solvent residual ratio at the time of peeling is too small, the tension of the wet film 16 required for peeling will be forced to be high. When the tension of the wet film 16 required for peeling is too high, the orientation degree may increase. Therefore, it is preferable to advance drying of the said flexible film 32 so that the solvent residual ratio at the time of peeling may not be less than 100%.

Drying of the casting film 32 is performed by supply of gas by the air supply unit 35. The progress of drying of the casting film 32, that is, the drying speed, is adjusted by controlling the temperature, flow rate, and flow rate of the gas from the nozzle 36b of the air supply unit 35.

Next, the highest set temperature T2 (see FIG. 3) will be described. This highest set temperature T2 is significant when the manufacturing efficiency is important. The maximum set temperature (T2) is {(doping gel point TG) + 3} ° C. Thereby, the film 23 is reliably manufactured by the conventional cooling gelation system and the manufacturing speed of the same level. That is, the temperature of the cast film 32 is set by setting the temperature of the circumferential surface 29a to be in the range of {(dope gel point TG) -3} ° C. or more and {(dope gel point TG) +3} ° C. or less. Is maintained in the range of {(dope gelation point (TG))-3} ° C or more {(dope gelation point (TG)) + 3} ° C or less until peeling. Thereby, the film which improved workability and rework property is manufactured at the speed | rate similar to the manufacturing speed of the conventional cooling gelation system. For example, in the case where the flexible film conveying distance is 10 m and the thickness of the film to be produced is 40 μm, the temperature of the peripheral surface 29a of the drum 29 is set to {((gel gel point TG of dope) +3} ° C. or less). In this case, the film 23 is generally manufactured at a speed of 80 m / min. On the other hand, in the same case, when the temperature of the circumferential surface 29a of the drum 29 is set to a temperature higher than {(dope gel point TG) +3} ° C., the temperature is less than 40 m / min. The film 23 may not be manufactured. The same applies to the case where a belt is used instead of the drum 29. When the maximum set temperature is {(gel point TG) +3} ° C., the longer the flexible film conveying distance is, the faster the film 23 is produced.

In addition, you may change said highest set temperature T2 to higher temperature according to prescription of dope 13 and the manufacturing speed made into the objective as mentioned above.

As mentioned above, this invention is applicable as long as it is the solution film forming which gelatinizes the casting film 32, and hardens. Moreover, this invention is applicable also when using the drum 29 as a support body like this embodiment. When a drum manufactures a film with wider width, it can manufacture a larger thing more easily than manufacturing a wider band. Therefore, the request for widening of the film 23 can be met.

The present invention is also applicable to the case where the dope 13 having different prescriptions is covalently produced to produce the film 23. In this case, gelation point TG is calculated | required about the dope softened in contact with the drum 29, and the minimum setting temperature T1 and the maximum setting temperature T2 are calculated | required based on this gelation point TG.

In addition, in order to improve processability and rework property more reliably or to improve more, it is preferable to peel the casting film 32 from the drum 29 by the following method.

The process of peeling is demonstrated concretely, referring FIG. 5 and FIG. In FIG. 5, FIG. 6, the arrow line Z1 shows the conveyance direction of the wet film 16, and the arrow line Z2 shows the width direction of the wet film 16. In FIG. In addition, the width direction of the circumferential surface 29a corresponds to the width direction Z2 of the wet film 16. 5 and 6 are schematic and the peeling roller 33 is drawn small with respect to the thickness of the wet film 16.

In the following description, the space on one film surface side peeled off from the drum 29 of the wet film 16 is referred to as the first space 51 and the space on the other film surface side is referred to as the second space 52. FIG. 6: is the figure which looked at the wet films 16 and 41 from the 1st space 51 side. The peeling roller 33 is arrange | positioned so that the longitudinal direction may correspond to the width direction of the circumferential surface of the drum 29. The peeling roller 33 is provided on the opposite side to the drum 29 with respect to the conveyance path of the wet film 16. That is, since the drum 29 is provided in the 1st space 51, the peeling roller 33 is provided in the 2nd space 52. As shown in FIG.

The peeling roller 33 is provided with the drive means 70 and the controller 71 which controls this drive means 70. By this drive means 70, the peeling roller 33 rotates to a circumferential direction at a predetermined rotational speed. The controller 71 controls the drive means 70 so that the peeling roller 33 may rotate at the set speed, when the signal of the rotational speed of the set peeling roller 33 is input.

The peeling roller 33 supports the wet film 16 which was guided in the circumferential surface, and conveys the wet film 16 by rotating. The drum 29 and the peeling roller 33 are arrange | positioned so that the wet film 16 may be wound up by the peeling roller 33, and the conveyance path downstream of the peeling roller 33 is defined. Thus, the flexible film 32 is peeled from the drum 29 by winding up the wet film 16 to the peeling roller 33 and conveying the wet film 16 to the peeling roller 33.

In addition, the peeling roller 33 may not necessarily be a drive roller, and what is called a driven roller driven by the circumferential surface contacting the wet film 16 conveyed may be sufficient. When the peeling roller 33 is a driven roller, another conveying means is provided downstream of the peeling roller 33. And the casting film 32 is peeled from the drum 29 by supporting the wet film 16 with the peeling roller 33, and conveying the wet film 16 with the conveying means provided.

The 41 is provided in the 2nd space 52 between the drum 29 and the peeling roller 33, and it controls so that the wet film 16 may be conveyed by the desired path | route. 41 includes a chamber 55, a pump 56, and a controller 57. The chamber 55 separates the space to be decompressed from the external space. The pump 56 sucks in the atmosphere inside the chamber 55. The controller 57 controls the suction force of the pump 56. When the signal corresponding to the value of the set pressure in the inside of the chamber 55 is input, the controller 57 adjusts the suction force of the pump 56 so that it may become the set pressure.

The chamber 55 includes a first member 61 that separates the second space 52 to be depressurized from the upstream outer space in the conveying direction Z1 of the wet film 16, and a downstream side. The third member 63 and the fourth member 64, which distinguishes from the external space of each side part of the width direction Z2, and the external member of which it distinguishes from an external space, and the external space below, are distinguished. Five members 65 are provided. The 1st-5th members 61-65 are plate shape, and among these, the 1st-4th members 61-64 are arrange | positioned in the standing posture. Moreover, in the chamber 55, the 1st opening 68 which opposes the wet film 16 is formed so that the 1st-4th members 61-64 may be enclosed, and the exterior of the chamber 55 will be provided. Gas is sucked in from the first opening 68.

The first member 61 is disposed to face the drum 29 and has a curved surface along the circumferential surface 29a of the drum 29. The 1st member 61 is arrange | positioned so that the distance with the drum 29 may be 100 micrometers or more and 2500 micrometers or less in consideration of the thickness of the flexible film 32. FIG. 61U of upstream ends of the 1st member 61 in the conveyance direction Z1 is located upstream rather than the downstream end 29D of the drum 29. As shown in FIG.

The second member 62 is disposed to face the peeling roller 33 and has a curved surface along the circumferential surface of the peeling roller 33. The 2nd member 62 is arrange | positioned so that the distance with the peeling roller 33 may be in the range of 100 micrometers or more and 2500 micrometers or less. The downstream end 62D of the second member 62 in the conveyance direction Z1 is located downstream from the upstream end 33U of the peeling roller 33. In the second member 62, a second opening 69 through which gas inside the chamber 55 flows is formed. The second opening 69 is connected to the pump 56.

When the wet film 16 is seen from above in FIG. 5, as shown in FIG. 6, the inner surface of each of the third member 63 and the fourth member 64 is a side edge of the wet film 16. It is arrange | positioned so that it may become outside rather than 16e. As a result, the wet film 16 until the path is stabilized does not strike the third member 63 and the fourth member 64. The opposing surface of the third member 63 and the fourth member 64 that faces the wet film 16 is, as seen in the present embodiment, as shown in FIG. 5 in the present embodiment. Although it is curved so that it does not overlap a path | route, it does not necessarily need to be a curved surface.

The inside of the chamber 55 enters a reduced pressure state by the suction of gas. When the inside of the chamber 55 is depressurized, the second space 52 between the drum 29 and the peeling roller 33 is also depressurized to become a pressure lower than the first space 51. Thereby, the wet film 16 toward the peeling roller 33 is attracted to the chamber 55 side, and is a path | route from a linear path | route (symbol A shown with the broken line in FIG. 5) to a curved path | route (indicated by the solid line in FIG. 5). Is changed, and when it sees from the side like FIG. 5, a conveyance path becomes convex toward the 2nd space 52 side. Thus, 41 is a suction unit which sucks the gas of the 2nd space 52 between the drum 29 and the peeling roller 33, and by this suction the drum 29 and the peeling roller 33 The 2nd space 52 in between is depressurized, and the conveyance path of the wet film 16 is made concave toward the 2nd space 52 side.

By making the conveyance path of the wet film 16 convex toward the 2nd space 52 side, the force which apply | occur | produces the longitudinal direction of the wet film 16 among the force | strengths applied to the wet film 16 for peeling is compared with the conventional one. It greatly reduces and more force is used for peeling out of the force provided. For this reason, the orientation in the direction along the film surface of the cellulose acylate which is a polymer of the wet film 16 is suppressed, and as a result, processing aptitude and reworkability are improved together more reliably, or it improves significantly.

In the conventional method, when the force of peeling is too large, the wet film 16 may be cut | disconnected at the time of peeling. In the case where the production speed is increased, the solvent residual ratio at the time of peeling is higher, so that the adhesion between the cast film 32 and the drum 29 is greater. Therefore, in the case of making the film forming speed faster, the peeling force becomes larger, so it is easy to cut. On the other hand, according to the said method of this invention, since the force provided for peeling under a fixed manufacturing speed can be made smaller, as a result, there also exists an effect that a manufacturing speed can be made larger. In addition, according to the above method, since the gas is not sprayed on the wet film 16 having a very high solvent residual ratio immediately after peeling, the smoothness of the film surface of the wet film 16 is maintained and the foreign matter Contamination by can also be avoided.

As mentioned above, the circumferential surface 29a of the drum 29 in the peeling position PP and the wet film 16 are controlled by controlling the path of conveyance of the wet film 16 toward the peeling roller 33. The angle θ1 to be formed can be increased. For this reason, it becomes easy to restrain the force required for peeling low.

As for angle (theta) 1 which the circumferential surface 29a of the drum 29 and the wet film 16 in the peeling position PP make, it is more preferable to set it as the range of 30 degrees or more and 80 degrees or less.

When the angle θ1 formed between the circumferential surface 29a of the drum 29 and the wet film 16 at the peeling position PP is increased, the winding center angle θ2 relative to the peeling roller 33 is a straight path. It becomes larger than the winding center angle in case of (A). When winding center angle (theta) 2 is easy to maintain large, the shape of the conveyance path between the drum 29 and the peeling roller 33 will also be easier to hold | maintain, while being convex.

In addition, winding center angle (theta) 2 is the center angle in the linear form which consists of the winding area | region 72 in which the wet film 16 was wound by the peeling roller 33, and the cross section circular center of the peeling roller 33. As shown in FIG.

From the viewpoint which enlarges the angle (theta) 1 which the circumferential surface 29a of the drum 29 in the peeling position PP and the wet film 16, and the winding center angle (theta) 2 make larger, this embodiment and Similarly, it is more preferable to make the peeling roller 33 into a drive roller instead of a driven roller. When maintaining the shape of the conveyance path which convexed to the 2nd space 52 side, or making it larger convex, what is necessary is just to reduce the rotational speed of the peeling roller 33 used as a drive roller. Thus, the angle (theta) 1 which the circumferential surface 29a of the drum 29 in the peeling position PP and the wet film 16 make, and the winding center angle (theta) 2 are wet toward the peeling roller 33. In addition to the method of making the conveyance path of the film 16 larger by only suction by the chamber 55, it can also make it larger by controlling the rotational speed of this drive roller using the peeling roller 33 as a drive roller.

In this embodiment, although the 2nd space 52 was depressurized so that the 2nd space 52 might be lower than the 1st space 51, this invention is not limited to this. For example, you may pressurize the 1st space 51 instead of or in addition to decompression of the 2nd space 52. FIG. However, this pressurization is pressurization at a constant pressure, not pressurization at dynamic pressure.

The pressurization as the positive pressure is performed by passing the straight path A of the first space 51 and the wet film 16 into the chamber so as to include a portion on the downstream side of the drum 29 and a portion on the upstream side of the peeling roller 33. It can be performed by repeating the conveyance operation which conveys a gas in this chamber for a fixed time, and the stop operation which stops a conveyance operation for a fixed time, enclosed in the chamber. According to this method, generation | occurrence | production of the dynamic pressure called injection of gas can be suppressed largely, and pressure can be applied with respect to the wet film 16 from the 1st space 51 side. In addition, even when the gap between the drum 29 and the peeling roller 33 is set to a very small gap of about several mm, according to this method, a pressure difference is reliably applied to the first space 51 and the second space 52. I can make it. Moreover, the smoothness of a film surface can be supported more reliably than to suck a gas from the slit-shaped opening extended in the width direction Z2.

There is another method as a method for forming a pressure difference in the first space 51 and the second space 52 up to the drum 29 and the peeling roller 33. For example, the wet film forming apparatus 17 without using the chamber 55 or the chamber (not shown) surrounding the straight path A of the first space 51 and the wet film 16. In the chamber (not shown) which comprises (refer FIG. 1), the partition member which distinguishes an internal space is provided, and there exists a method of making the pressure difference. By controlling the pressure of each space formed by the partition member, respectively, a pressure difference can be made to the 1st space 51 and the 2nd space 52 below than the conveyance path of the wet film 16. FIG. have. In addition, a chamber (not shown) constituting the wet film forming apparatus 17 covers the drum 29, the flexible die 31, the duct 36, and the peeling roller 33 so as to be distinguished from the external space. It can be formed. When the distance between the drum 29 and the peeling roller 33 is 5000 micrometers or more, it is more preferable to make the pressure difference using the chamber 55. FIG. When the distance between the drum 29 and the peeling roller 33 is less than 5000 μm, the chamber (not shown) surrounding the straight path A of the chamber 55 or the first space 51 and the wet film 16 is illustrated. ), A chamber (not shown) constituting the wet film forming apparatus 17 may be divided into partition members and a pressure difference may be obtained.

The difference of the pressure of the 1st space 51 and the 2nd space 52 is based on the solvent residual ratio of the wet film 16 until it passes through the winding area | region in the peeling roller 33 from the peeling position PP. It is desirable to make a decision based on this. It is preferable to make a conveyance path larger convex by increasing a pressure difference, so that a solvent residual rate is large. This is because the larger the solvent residual ratio is, the stronger the adhesion between the drum 29 and the cast film 32 is, and the wet film 16 is more likely to break.

The peeling position PP is formed in the downstream side in the rotation direction of the drum 29 so that it may go toward the center in the width direction Z2. For this reason, the force applied to the longitudinal direction of the wet film 16 at the time of peeling becomes large toward the center in the width direction Z2, and surface orientation becomes large. Therefore, in the peeling position PP, it is more preferable to make the pressure of the 2nd space 52 low as it goes to the center. Thereby, the film 23 whose surface orientation is constant in the width direction Z2 can be manufactured. In order to lower the pressure of the second space 52 as it goes toward the center at the peeling position PP, for example, an independent chamber (not shown) is further provided inside the chamber 55. There is a method of independently controlling each internal pressure between the chamber and the chamber 55.

The film 23 obtained by said method fully satisfies a practical use level with respect to the uniformity of thickness. However, in the future, there is a possibility that further improvement in thickness uniformity may be required depending on the use or the like. What is necessary is just to perform the following method in order to improve the thickness uniformity of the film 23 further. In addition, the following method can be performed even if it does not arrange | position (41), and only one film forming solution and a tenter which do not hold | maintain the temperature of a cast film above ((TG) -3) degreeC are carried out. It is also applicable to other well-known solution film forming, such as unused solution film forming and solution film forming using a band instead of the drum 29 as the flexible support.

As shown in FIG. 7, the flexible die 31, the drum 29, the ducts 36, and 41 are accommodated in the flexible chamber 45. The pressure reduction chamber 44 mentioned above is arrange | positioned at the upstream side of the casting die 31 in the rotation direction of the drum 29, and this pressure reduction chamber 44 is also accommodated in the casting chamber 45. As shown in FIG.

The flexible chamber 45 includes a first seal member 81 between the flexible die 31 and the duct 36, and the second seal member 82 between the peeling roller 33 and the pressure reduction chamber 44. ). The 1st seal member 81 and the 2nd seal member 82 are provided in the posture which stood up toward the drum 29 in the inner wall of the flexible chamber 45. As shown in FIG. By this 1st seal member 81 and the 2nd seal member 82, the inside of the flexible chamber 45 is the 1st area | region 83 containing the flexible die 31 and the pressure reduction chamber 44, and the duct 36 ) And the second region 84 including the peeling roller 33. However, there is a slight gap in consideration of the thickness of the flexible film 32 between the tip of the first seal member 81 and the drum 29 so that the flexible film 32 passing through and the first seal member 81 do not contact each other. Is formed. In addition, a slight gap is formed between the tip of the second seal member 82 and the drum 29 so that the drum 29 and the second seal member 82 do not contact each other.

In the present embodiment, the flexible chamber 45 is divided into two regions of the first region 83 and the second region 84. However, a seal member (not shown) such as the first seal member 81 or the second seal member 82 in the second region 84 in accordance with the purpose of speed adjustment such as cooling or drying of the flexible film 32. ) May be further provided to divide the second region 84 into more regions.

The first seal member 81 has a partition plate 81a and a labyrinth seal 81b, and the second seal member 82 has a partition plate 82a and a labyrinth seal 82b. The partition plate 81a and the partition plate 82a are respectively attached to the inner wall of the flexible chamber 45, and are extended in the posture which stood up toward the drum 29. As shown in FIG. The labyrinth seal 81b is attached to the front end of the drum 29 side of the partition plate 81a, and the labyrinth seal 82b is attached to the front end of the drum 29 side of the partition plate 82a.

The flexible chamber 45 is provided with the viscosity control apparatus 87 connected to the 1st area | region 83, and the supply / exhaust unit 88 connected to the 2nd area | region 84. As shown in FIG.

The air supply / exhaust unit 88 includes an air supply unit 91, an exhaust unit 92, and a control unit 93. The air supply unit 91 supplies gas to the second region 84. The exhaust unit 92 discharges the gas in the second region 84 to the outside. The control unit 93 controls the air supply unit 91 and the exhaust unit 92. For example, the control part 93 controls on / off of the air supply by the air supply part 91, the air supply flow volume, and the temperature, humidity, or solvent gas concentration of the gas which are sent, and the gas suction by the exhaust part 92 is carried out. Control on / off and exhaust flow rate. By this supply-discharge unit 88, the temperature, humidity, and solvent gas concentration of the 2nd area | region 84 are respectively controlled to a predetermined range.

The viscosity control device 87 has a viscosity calculation unit 95 and a temperature control unit 96. The viscosity calculation unit 95 includes a flow meter 97, a detection unit 98, and a viscosity calculation unit 99.

The flowmeter 97 is provided in the piping upstream of the casting die 31, and measures and outputs the flow rate of the dope 13. The detection part 98 is provided in the piping between the flowmeter 97 and the casting die 31. As shown in FIG. The position of the detection part 98 may be upstream of the flowmeter 97. The pressure loss of the dope 13 from the casting die 31 toward the drum 29 is detected. Specifically, the detection unit 98 detects the pressure of the dope 13 guided to the casting die 31, and detects the pressure loss from the detected value and the pressure of the dope 13 flowing out of the casting die 31. Calculate and output In addition, the pressure of the dope 13 which flowed out from the casting die 31 does not need to be measured, and atmospheric pressure may be regarded as the pressure value of the dope 13 which flowed out from the casting die 31.

The viscosity calculation part 99 has an input side connected to the flowmeter 97 and the detection part 98, and the output side connected to the temperature calculation part 101 of the temperature control unit 96. When the flow rate of the dope 13, the pressure loss in the casting die 31, and the flow path shape parameter of the casting die 31 which flows out the dope 13 are input, the viscosity calculation part 99 inputs into these input signals. Based on this, the viscosity of the dope 13 is calculated and output. The viscosity is calculated by the following formula (1). In this way, the viscosity calculation unit 95 calculates the viscosity from the pressure loss with respect to the dope 13 flowing out from the casting die 31. In the following formula, Q is the flow rate of the dope 13 (unit: mm ³ / s), (DELTA) P is a pressure loss in the casting die 31, h, L, and W flow out the dope 13. It is a flow path shape parameter of the casting die 31 to be described. h is the space | interval (unit: mm) of the clearance gap in the slit-shaped outlet of the casting die 31, and when the outlet is rectangular, the length of a short side corresponds to this. (eta) is a viscosity (unit; Pa * s). L is the plate length (unit; mm). The flow path of the dope 13 in the casting die 31 is a block (not shown) of the upstream and the block (not shown) of the upstream in the rotation direction of the drum 29 as well as these, It is formed surrounded by side plates disposed on each side of the block. The width | variety (length in the width direction of a drum) of a flow path is constant for the fixed range from the outlet to the flow direction upstream of the dope 13 in the casting die 31. As shown in FIG. The length in the flow direction of the dope 13 of the flow path which becomes this fixed width corresponds to L. FIG. W is the length (unit: mm) of the gap in the slit-shaped outlet of the casting die 31, and when the outlet is rectangular, the length of the long side corresponds to this.

ΔP = 12ηLQ / Wh ³ (One)

The viscosity of the dope 13 which flows out from the casting die 31 can also be calculated | required by another well-known method. In the case of obtaining the viscosity by another known method, since the viscosity by the other method to be used and the viscosity by the above method have a constant correlation, the viscosity of the other method to be used and the viscosity by the above method may be corresponded. However, in the solution film formation which casts the dope 13, since a high shear is applied with respect to the dope in the casting die 31, it is preferable to calculate | require a viscosity by said method from a viewpoint of controlling a viscosity more precisely. .

The temperature control unit 96 includes a temperature calculating unit 101, a control unit 102, and an air supply unit 103. The temperature control unit 96 may include the exhaust part 104. When temperature and a flow volume are input, the air supply part 103 outflows the gas of the input temperature, for example, air at the input flow volume. When a flow rate is input, the exhaust part 104 sucks gas at the input flow rate and discharges it to the outside.

The control unit 102 is connected to the air supply unit 103 and the flexible die 31. When the temperature of the dope 13 made into the objective (henceforth dope object temperature) is input, the control part 102 calculates the temperature and flow volume of the gas which should flow out from the air supply part 103, and supplies the air supply part 103. ) To control the air supply unit 103. The flexible die 31 is equipped with a temperature regulator (not shown) for adjusting the temperature of the flow path of the dope 13 formed in the inside, and when the dope object temperature is input, the control part 102 receives a flexible die ( The set temperature of 31 is calculated, the set temperature of the flexible die 31 is output to the temperature regulator of the flexible die 31, and the temperature regulator is controlled.

If there is an exhaust section 104, the control unit 102 also connects to the exhaust section 104. When the dope object temperature is input, the control unit 102 calculates the flow rate of the gas to be sucked by the exhaust unit 104, outputs the output to the exhaust unit 104, and controls the exhaust unit 104.

The temperature calculation part 101 has an input side connected to the viscosity calculation part 99 of the viscosity calculation unit 95, and an output side connected to the control part 102. In the temperature calculation part 101, the relationship between the viscosity and temperature for every prescription of the dope 13 is input. When the viscosity of the dope 13 is input, the temperature calculation part 101 determines whether this viscosity is a range of 7 Pa * s or more and 9 Pa * s or less. When the viscosity is in the range of 7 Pa · s or more and 9 Pa · s or less, the dope target temperature is not output to the control unit 102, but when the viscosity is less than 7 Pa · s or larger than 9 Pa · s, the control unit 102 Output the dope target temperature. The detail of the output of the dope object temperature in the temperature calculation part 101 is mentioned later using another figure.

The viscosity control apparatus 87 of the said structure controls the temperature of the dope 13 cast by the drum 29 as follows. First, the flowmeter 97 of the viscosity calculation unit 95 measures the flow volume of the dope 13 which goes to the casting die 31, and outputs it to the viscosity calculation part 99. FIG. The detection unit 98 detects the pressure loss of the dope 13 from the casting die 31 toward the drum 29 and outputs it to the viscosity calculation unit 99. The viscosity calculation part 99 is a flow volume shape of the dope 13 guide | induced to the casting die 31, the pressure loss in the casting die 31, and the flow path shape parameter of the casting die 31 which flows out the dope 13. When is input, the viscosity of the dope 13 toward the drum 29 from the casting die 31 is computed from these input signals. The viscosity calculation part 99 outputs a calculation signal to the temperature calculation part 101 of the temperature control unit 96.

The relationship between the viscosity of dope 13 and temperature is previously input to the temperature calculation part 101. The temperature calculation part 101 specifies the temperature range of the dope 13 corresponding to a predetermined viscosity range based on this relationship. When the calculation signal of the viscosity calculation part 99 is input, the temperature calculation part 101 determines whether the viscosity of the dope 13 corresponding to this calculation signal is a predetermined viscosity range. In the case where it is determined that the viscosity is larger than the upper limit of the predetermined viscosity range, first, the temperature extracted from the temperature range of the dope specified is output to the control unit 102 as the dope target temperature. When it is determined that the viscosity is a predetermined temperature range, the temperature calculation unit 101 does not output to the control unit 102.

When the dope object temperature is input, the control unit 102 calculates the temperature and the flow rate of the gas to flow out of the air supply unit 103 and outputs it to the air supply unit 103. The air supply unit 103 adjusts the temperature of the gas to the input temperature, and supplies the temperature-regulated gas to the first region 83 at the flow rate at which the temperature is adjusted. By this supply, the temperature of the first region 83 is adjusted. The temperature of the dope 13 out of the casting die 31 is influenced by the temperature of an atmosphere. For example, when the dope 13 comes out from the casting die 31, it may become substantially equal to the atmospheric temperature, and in this case, what is necessary is just to make the temperature of the 1st area | region 83 the dope object temperature. When making the temperature of the 1st area | region 83 into dope object temperature, the control part 102 calculates the temperature of the gas which should flow out from the air supply part 103, for example to the same temperature as dope object temperature.

Moreover, when the dope object temperature is input, the control part 102 calculates the set temperature of the casting die 31, and outputs it to the temperature regulator of the casting die 31. FIG. The temperature controller adjusts the temperature of the flexible die 31 so as to be the input set temperature. By adjusting the temperature of the casting die 31, the temperature of the dope 13 is adjusted while passing through the internal flow path. The control unit calculates the set temperature of the flexible die 31 at the same temperature as the dope target temperature, for example.

In this embodiment, by adjusting the temperature of both the 1st area | region 83 and the casting die 31, the temperature of dope is precisely adjusted so that it may become a dope object temperature. However, when the temperature of the dope 13 is adjusted so that it may become a dope object temperature by the temperature adjustment of either one of the 1st area | region 83 and the casting die 31, any one temperature adjustment may be sufficient.

In addition, the temperature of the dope 13 can be adjusted also by injecting the temperature-regulated gas into the dope 13 which flowed out from the casting die 31. However, in this method, the shape of the dope 13 which flowed out from the casting die 31 is disturbed by dynamic pressure by the injection of gas, and the casting film 32 often does not smooth the membrane surface, which is undesirable. not. On the other hand, according to this embodiment which temperature-adjusts the whole atmosphere of the 1st area | region 83 by gas supply from the air supply part 103 to the 1st area | region 83, the pressure applied to the casting film 32 is Since it is static pressure instead of dynamic pressure, since the shape of the dope 13 which flowed out from the casting die 31 does not disturb, it is preferable.

When the exhaust part 104 exists, the control part 102 calculates the flow volume of the gas which should be attracted to the exhaust part 104, and outputs it to the exhaust part 104, when a dope object temperature is input. The exhaust unit 104 sucks the atmosphere of the first region 83 at the input flow rate. By this suction, the temperature of the first region 83 is adjusted more quickly.

As described above, the dope 13 cast on the drum 29 is adjusted to the dope target temperature, whereby the viscosity is controlled in a predetermined range. The predetermined viscosity range is a viscosity range of 7 Pa · s or more and 9 Pa · s or less. If the viscosity is 7 Pa · s or more, the uniformity of the thickness of the film is very excellent compared to less than 7 Pa · s. Moreover, when a viscosity is larger than 9 Pa * s, although the film surface of the film 23 often becomes a rough skin (shark skin) shape, a shark skin is reliably prevented by making a viscosity 9 Pa * s or less.

The calculation method of the dope target temperature by the temperature calculation part 101 is demonstrated, referring FIG. In FIG. 8, the vertical axis | shaft is the temperature of the dope 13, and it means that temperature is higher, so that it is upper. The horizontal axis is the viscosity (unit; Pa · s) of the dope 13.

The curve A shown by the broken line and the curve B shown by the solid line are graphs which show the relationship between the temperature and viscosity which were respectively obtained about the dope 13 of the prescription which mutually differs. The relationship between such temperature and viscosity is previously input to the temperature calculating part 101. Curve A and curve B differ from each other in the relationship between temperature and a viscosity. In this way, the relationship between the temperature and the viscosity depends on the prescription of the dope 13. Therefore, for each prescription of dope 13, the relationship between temperature and a viscosity is calculated | required, and the calculated | required relationship is input into the temperature calculation part 101, respectively.

The temperature calculation part 101 specifies the temperature of the dope 13 corresponding to the predetermined temperature range that the viscosity of the dope 13 is 7 Pa * s or more and 9 Pa * s or less. For example, about the curve A of FIG. 8, the temperature of the dope 13 whose viscosity is 7 Pa.s is specified, this is made TA7 (degreeC), and the temperature of the dope 13 whose viscosity is 9 Pa.s. Is specified and this is set to TA9 (° C). As shown in FIG. 8, since the viscosity of the dope 13 is so high that temperature is low, the dope 13 corresponding to the predetermined temperature range whose viscosity of dope 13 is 7 Pa * s or more and 9 Pa * s or less. The temperature range of is specified in the range of TA9 (degreeC) or more and TA7 (degreeC) or less. Thus, when the temperature corresponding to each of the lower limit and the upper limit of the predetermined viscosity range is specified, the temperature range corresponding to the predetermined viscosity range is specified. In FIG. 8, about the dope 13 of curve A, the code | symbol TAR is attached | subjected to the specified temperature range.

The temperature calculator 101 extracts one temperature from a specific temperature range TAR and outputs the extracted temperature as the dope target temperature. The temperature to extract is not specifically limited, It may be arbitrary. However, the closer the viscosity is to 9 Pa · s, the more the thickness of the film 23 tends to be more uniform. Therefore, in consideration of this tendency, the temperature calculation unit extracts the temperature TA9 (° C.) corresponding to 9 Pa · s. What is necessary is to control the output of (101). In addition, when the mass ratio of the solvent 12 in the dope 13 is very high, the temperature at which a viscosity becomes 9 Pa.s is too low, and a limit may arise in a manufacturing speed. In such a case, the output of the temperature calculation unit 101 may be controlled so as to give priority to the manufacturing speed and the like to extract the temperature at which the viscosity is lower than 9 Pa · s.

Also in the case of the dope 13 of the curve B, the dope target temperature is output similarly to the case of the dope 13 of the curve A mentioned above. That is as follows. First, the temperature of the dope 13 whose viscosity is 7Pa * s is specified, it is set as (TB7) (degreeC), the temperature of the dope 13 whose viscosity is 9Pa * s is specified, and this is (TB9) (degreeC). ) Thereby, the temperature range of the dope 13 corresponding to the predetermined temperature range that the viscosity of the dope 13 is 7 Pa * s or more and 9 Pa * s or less is (TB9) (degreeC) or more (TB7) (degreeC) or less It is specified by the range. In FIG. 8, code | symbol TBR is attached | subjected to the specified temperature range with respect to the dope 13 of the curve B. In FIG. The temperature calculator 101 extracts one temperature from a specific temperature range TBR and outputs the extracted temperature as the dope target temperature.

In order to make the thickness of the film 23 more uniform, the thickness of the cast film 32 is made more uniform. Conventionally, in order to make thickness of a casting film more uniform, the method of making the viscosity of dope lower and thereby making the height of one film surface exposed by the casting film constant (leveling) is used. In addition, conventionally, in order to make the viscosity of a dope lower, the mass ratio of the solvent in dope is made more large (lower the mass ratio of solid content) in the range which does not apply excessive load in the drying process of drying a wet film. There are many cases. Moreover, the temperature of the dope which is flexible is conventionally set at the comparatively high temperature of the grade which the solvent contained in dope does not evaporate rapidly. For example, in the case of dope of the cellulose acylate which uses dichloromethane as one component of a solvent, the dope made into the temperature of about 35 degreeC was cast. In contrast, in the present invention, the viscosity of the dope 13 is set to a range of 7 Pa · s or more and 9 Pa · s or less than conventionally. And control of a viscosity is performed by adjusting the temperature of dope 13, without changing the mass ratio of the solvent 12 (refer FIG. 1) in dope 13. Thus, the temperature adjustment of the dope 13 is performed for viscosity control, and for this reason, the temperature of the dope 13 is set very low than before.

According to the above method, the uniformity of the thickness of the film 23 can be improved more, without changing the prescription of the dope 13. For example, for the purpose of smoothing the exposed membrane surface of the flexible membrane, the conventional method of increasing the mass ratio of the solvent in the dope does not need to be used in the above method. For this reason, it is not necessary to change the conditions of the post-process according to the change of the prescription of the dope 13, and there is no fear of lowering a manufacturing speed. The conditions of the post-process are, for example, blowing conditions in the duct 36, blowing conditions in the first tenter 18 and stretching conditions. Moreover, since the temperature of the dope 13 can be easily adjusted by said method irrespective of the prescription of dope, a viscosity is controlled easily. Moreover, in the said method, in order to set a viscosity to said predetermined range higher than the conventional, temperature of dope is adjusted to be lower than conventional. For this reason, it is not necessary to worry about foaming of the dope 13 and the casting film 32 by the rapid evaporation of the solvent 12.

Below, the Example as this invention and the comparative example with respect to this invention are described.

[Example 1]

The film 23 of 60 micrometers in thickness was manufactured from the dope 13 of the following prescription using the solution film forming installation 10 shown in FIG. However, in the present Example, the viscosity calculation unit 95 arrange | positioned at the solution film forming installation 10 and the temperature calculation part 101 of the temperature control unit 96 were not used. 35 degreeC was input to the control part 102 as dope object temperature, and the temperature of the dope 13 which flows out from the casting die 31 was adjusted so that it might become the same as dope object temperature. Therefore, the temperature of the flexible dope 13 (dope 13 at the time of flowing out from the flexible die 31) is 35 degreeC. Gel point TG of the dope 13 was 6 degreeC. Experiment 1-experiment 14 which performed the temperature of the circumferential surface 29a of the drum 29 at different temperature were implemented. The temperature of the circumferential surface 29a of the drum 29 in each experiment is shown in Table 1.

<Prescription of dope 13>

Solid component ... 20 mass% in mass ratio in dope 13

It is mixture of solvent ... dichloromethane and alcohol, and dichloromethane: alcohol = 80:20

In addition, said solid component is TAC as a polymer 11, a plasticizer, a mat agent, and a UV absorber.

About the film 23 obtained by each experiment, workability and reworkability were evaluated with the following method and reference | standard. About a result, it shows in Table 1.

(1) processing aptitude

The obtained film 23 was laminated | stacked and adhere | attached on both surfaces of a polarizing film via an adhesive agent, and the polarizing plate was produced. The polarizing plate was punched into a rectangle of 10 cm x 10 cm with a knife to obtain a sample for evaluation. From the edge of this evaluation sample, ie, the cut surface, whether or not cracks were generated inside the film 23 and the degree of the identified cracks were evaluated, and this was evaluated as workability. Evaluation was performed based on the following criteria. A crack may be a crack which goes inward from the cut surface of the film 23, and may be peeling between a polarizing film and the film 23. FIG. In the following reference | standards, A-C is a level with which processing aptitude passes, and D is a level with which processing aptitude fails.

A: A crack is not observed, or a crack has generate | occur | produced, but the range of the crack which generate | occur | produced is less than 25% of the length of a long side.

B: The range where a crack generate | occur | produces is stable in the range of 25% or more and less than 50% of the length of a long side.

C: The range where a crack generate | occur | produces is in the range of 50% or more and less than 75% of the length of a long side.

D: The range where a crack generate | occur | produces is 75% or more of the length of a long side.

 (2) reworkability

The obtained film 23 was laminated | stacked and adhere | attached on both surfaces of a polarizing film via an adhesive agent, and the polarizing plate was produced. After attaching a polarizing plate to a glass substrate, it peeled off from the glass substrate. It confirmed visually about the grade which the film 23 on the glass substrate did not peel off, and evaluated the rework property based on the following criteria. In the following criteria, A to C are levels at which the reworkability is passed, and D is a level at which the reworkability is failed.

A: What is left without peeling off is not confirmed at all.

B: It is the thing which remains without being slightly stripped off.

C: There is a thing which remains without being peeled off a little, but is practically no problem.

D: There are many things left without peeling.

Example
Comparative Example Experiment number Type of polymer Film thickness (μm) Temperature of the peripheral surface of the drum (℃) Processing aptitude Reworkability Comparative Example 1 Comparative Experiment 7 TAC 60 TG-10 D D Comparative Experiment 6 TAC 60 TG-9 D D Comparative Experiment 5 TAC 60 TG-8 D D Comparative Experiment 4 TAC 60 TG-7 D D Comparative Experiment 3 TAC 60 TG-6 D D Comparative Experiment 2 TAC 60 TG-5 D D Comparative Experiment 1 TAC 60 TG-4 D D Example 1 Experiment 1 TAC 60 TG-3 A A Experiment 2 TAC 60 TG-2 A A Experiment 3 TAC 60 TG-1 A A Experiment 4 TAC 60 TG A A Experiment 5 TAC 60 TG + 1 A A Experiment 6 TAC 60 TG + 2 A A Experiment 7 TAC 60 TG + 3 A A Experiment 8 TAC 60 TG + 4 A A Experiment 9 TAC 60 TG + 5 A A Experiment 10 TAC 60 TG + 6 A A Experiment 11 TAC 60 TG + 7 A A Experiment 12 TAC 60 TG + 8 A A Experiment 13 TAC 60 TG + 9 A A Experiment 14 TAC 60 TG + 10 A A

Types of polymers; TAC

Thickness of the film; 60 μm

[Comparative Example 1]

Comparative Experiment 1 to Comparative Experiment 7 in which the temperature of the circumferential surface 29a of the drum 29 was set to different temperatures were performed. The temperature of the circumferential surface 29a of the drum 29 in each comparison experiment is shown in Table 1. Other conditions are the same as in Example 1.

About the film obtained by each comparative experiment, processability and reworkability were evaluated by the same method and reference | standard as Example 1, respectively. Table 1 shows the results of workability and rework performance.

[Example 2]

The film 23 of 40 micrometers in thickness was manufactured from the dope 13 of the prescription similar to Example 1. Experiment 1 to experiment 14 were performed in which the temperature of the peripheral surface 29a of the drum 29 was set to a different temperature, respectively. The temperature of the circumferential surface 29a of the drum 29 in each experiment is shown in Table 2. Other conditions are the same as in Example 1.

About the film 23 obtained by each experiment, workability and reworkability were evaluated by the same method and reference | standard as Example 1, respectively. Table 2 shows the results of workability and rework performance.

Example
Comparative Example Experiment number Type of polymer Film thickness (μm) Temperature of the peripheral surface of the drum (℃) Processing aptitude Reworkability Comparative Example 2 Comparative Experiment 7 TAC 40 TG-10 D D Comparative Experiment 6 TAC 40 TG-9 D D Comparative Experiment 5 TAC 40 TG-8 D D Comparative Experiment 4 TAC 40 TG-7 D D Comparative Experiment 3 TAC 40 TG-6 D D Comparative Experiment 2 TAC 40 TG-5 D D Comparative Experiment 1 TAC 40 TG-4 D D Example 2 Experiment 1 TAC 40 TG-3 A A Experiment 2 TAC 40 TG-2 A A Experiment 3 TAC 40 TG-1 A A Experiment 4 TAC 40 TG A A Experiment 5 TAC 40 TG + 1 A A Experiment 6 TAC 40 TG + 2 A A Experiment 7 TAC 40 TG + 3 A A Experiment 8 TAC 40 TG + 4 A A Experiment 9 TAC 40 TG + 5 A A Experiment 10 TAC 40 TG + 6 A A Experiment 11 TAC 40 TG + 7 A A Experiment 12 TAC 40 TG + 8 A A Experiment 13 TAC 40 TG + 9 A A Experiment 14 TAC 40 TG + 10 A A

Types of polymers; TAC

Thickness of the film; 40 μm

[Comparative example 2]

Comparative Experiment 1 to Comparative Experiment 7 in which the temperature of the circumferential surface 29a of the drum 29 was set to different temperatures were performed. The temperature of the circumferential surface 29a of the drum 29 in each comparison experiment is shown in Table 2. Other conditions are the same as in Example 2.

About the film obtained by each comparative experiment, processability and reworkability were evaluated by the same method and reference | standard as Example 1, respectively. Table 2 shows the results of workability and rework performance.

EXAMPLE 3

The polymer 11 in the dope 13 of Example 1 was changed into cellulose diacetate (DAC). The gel point (TG) of the dope 13 was -25 degreeC. From this dope 13, the film 23 of 40 micrometers in thickness was manufactured. Experiment 1 to experiment 14 were performed in which the temperature of the peripheral surface 29a of the drum 29 was set to a different temperature, respectively. The temperature of the peripheral surface 29a of the drum 29 in each experiment is shown in Table 3. Other conditions are the same as in Example 1.

About the film 23 obtained by each experiment, workability and reworkability were evaluated by the method and reference | standard similar to Example 1, respectively. Table 3 shows the results of workability and rework performance.

Example
Comparative Example Experiment number Type of polymer Film thickness
(μm) Temperature of the peripheral surface of the drum (℃) Processing aptitude Reworkability Comparative Example 3 Comparative Experiment 7 DAC 40 TG-10 D D Comparative Experiment 6 DAC 40 TG-9 D D Comparative Experiment 5 DAC 40 TG-8 D D Comparative Experiment 4 DAC 40 TG-7 D D Comparative Experiment 3 DAC 40 TG-6 D D Comparative Experiment 2 DAC 40 TG-5 D D Comparative Experiment 1 DAC 40 TG-4 D D Example 3 Experiment 1 DAC 40 TG-3 A A Experiment 2 DAC 40 TG-2 A A Experiment 3 DAC 40 TG-1 A A Experiment 4 DAC 40 TG A A Experiment 5 DAC 40 TG + 1 A A Experiment 6 DAC 40 TG + 2 A A Experiment 7 DAC 40 TG + 3 A A Experiment 8 DAC 40 TG + 4 A A Experiment 9 DAC 40 TG + 5 A A Experiment 10 DAC 40 TG + 6 A A Experiment 11 DAC 40 TG + 7 A A Experiment 12 DAC 40 TG + 8 A A Experiment 13 DAC 40 TG + 9 A A Experiment 14 DAC 40 TG + 10 A A

Types of polymers; DAC

Thickness of the film; 40 μm

[Comparative Example 3]

Comparative Experiment 1 to Comparative Experiment 7 in which the temperature of the circumferential surface 29a of the drum 29 was set to different temperatures were performed. The temperature of the circumferential surface 29a of the drum 29 in each comparison experiment is shown in Table 3. Other conditions are the same as in Example 3.

About the film obtained by each comparative experiment, processability and reworkability were evaluated by the same method and reference | standard as Example 1, respectively. Table 3 shows the results of workability and rework performance.

EXAMPLE 4

The polymer 11 in the dope 13 of Example 1 was changed into cellulose acetate propionate (CAP). Gel point TG of dope 13 was -10 degreeC. From this dope 13, the film 23 of 40 micrometers in thickness was manufactured. Experiment 1 to experiment 14 were performed in which the temperature of the peripheral surface 29a of the drum 29 was set to a different temperature, respectively. The temperature of the peripheral surface 29a of the drum 29 in each experiment is shown in Table 4. Other conditions are the same as in Example 1.

About the film 23 obtained by each experiment, workability and reworkability were evaluated by the same method and reference | standard in Example 1, respectively. Table 4 shows the results of workability and rework performance.

Example
Comparative Example Experiment number Type of polymer Film thickness
(μm) Temperature of the peripheral surface of the drum (℃) Processing aptitude Reworkability Comparative Example 4 Comparative Experiment 7 CAP 40 TG-10 D D Comparative Experiment 6 CAP 40 TG-9 D D Comparative Experiment 5 CAP 40 TG-8 D D Comparative Experiment 4 CAP 40 TG-7 D D Comparative Experiment 3 CAP 40 TG-6 D D Comparative Experiment 2 CAP 40 TG-5 D D Comparative Experiment 1 CAP 40 TG-4 D D Example 4 Experiment 1 CAP 40 TG-3 A A Experiment 2 CAP 40 TG-2 A A Experiment 3 CAP 40 TG-1 A A Experiment 4 CAP 40 TG A A Experiment 5 CAP 40 TG + 1 A A Experiment 6 CAP 40 TG + 2 A A Experiment 7 CAP 40 TG + 3 A A Experiment 8 CAP 40 TG + 4 A A Experiment 9 CAP 40 TG + 5 A A Experiment 10 CAP 40 TG + 6 A A Experiment 11 CAP 40 TG + 7 A A Experiment 12 CAP 40 TG + 8 A A Experiment 13 CAP 40 TG + 9 A A Experiment 14 CAP 40 TG + 10 A A

Types of polymers; CAP

Thickness of the film; 40 μm

[Comparative Example 4]

Comparative Experiment 1 to Comparative Experiment 7 in which the temperature of the circumferential surface 29a of the drum 29 was set to different temperatures were performed. The temperature of the circumferential surface 29a of the drum 29 in each comparison experiment is shown in Table 4. Other conditions are the same as in Example 4.

About the film obtained by each comparative experiment, workability and reworkability were evaluated by the same method and reference | standard in Example 1, respectively. Table 4 shows the results of workability and rework performance.

EXAMPLE 5

The viscosity of the dope 13 was computed using the viscosity calculation unit 95 arrange | positioned at the solution film-forming installation 10. The temperature of flexible dope is 35 degreeC, and other conditions are the same as that of Experiment 1 of Example 1. About the obtained film 23, the uniformity of thickness was evaluated with the following method and reference | standard, and this was made into experiment 1. Table 5 shows the evaluation results of the uniformity of the viscosity and the thickness of the dope 13.

(3) thickness uniformity

From the obtained elongate film 23, it sampled by the magnitude | size of 2m in length and 2m in width. The sampled sheet-like film 23 is placed under a straight fluorescent lamp so that the longitudinal direction of the straight fluorescent lamp is substantially coincident in the width direction of the obtained long film 23. Light of a straight fluorescent lamp is irradiated to the film 23, and the straight fluorescent lamp is reflected on the film 23. Among the contours (edge lines) of the straight fluorescent lamp image reflected on the film 23, the degree of linearity of the edge lines in the longitudinal direction of the straight fluorescent lamp was evaluated to make this an evaluation of the uniformity of the thickness of the film 23. The degree of linearity is determined by visually identifying the non-linear portion of the longitudinal edge line of the straight fluorescent lamp, and when the length of the range is X, the X of the length Y from one end of the edge line to the other end. A percentage (unit;%) was calculated | required and the following references | standards evaluated. In the following criteria, A to C are levels where thickness uniformity is passed from the current practical point of view, and D is a level at which thickness uniformity is rejected from the current practical point of view. In addition, C is a level which may become rejected in the future depending on a use.

A; edge line is straight from one end to the other

B; less than 20% of non-linear parts of edge line

C; less than 50% of non-linear parts of edge line

D; 50% or more of non-linear parts of edge lines

Experiment 1-experiment 10 were implemented with the following method. About the dope 13 used by the experiment 1 of Example 1, the relationship between temperature and viscosity was calculated | required. And the temperature of dope 13 was adjusted so that a viscosity might become a viscosity shown in the "viscosity of dope" column of Table 5. The temperature of the dope 13 is performed by inputting the "dope object temperature" (unit; degreeC) of Table 5 as the dope object temperature to the control part 102, and temperature dope 13 so that it may become the same as this dope object temperature. Adjusted. Therefore, the temperature of the flexible dope 13 (dope 13 at the time of flowing out from the flexible die 31) is the same as the dope target temperature input to the control part 102. FIG. The viscosity of the dope 13 which adjusted the temperature to the dope target temperature using the viscosity calculation unit 95 arrange | positioned at the solution film-forming installation 10, and it is a viscosity shown in the "viscosity of dope" column of Table 5 Confirmed. Other conditions are the same as those in Experiment 1.

In the same manner as in Experiment 1, the film 23 obtained in each experiment was evaluated for uniformity in thickness. The results of the evaluation are shown in Table 5.

Experiment number Viscosity of dope (Pas) Temperature of dope (℃) Evaluation results Experiment 1 5 35 C Experiment 2 5.5 34 C Experiment 3 6 30 C Experiment 4 7 29 B Experiment 5 7.5 28 B Experiment 6 8.5 27 A Experiment 7 9 26 A Experiment 8 9.5 25 A Experiment 9 10 23 C Experiment 10 11 20 C

Claims (9)

Forming a cast film by continuously casting a dope on a support;
Step to make a said wet film by peeling from the said support body in the state in which the said solvent remains;
Maintaining the temperature of the flexible film until the time of peeling so as not to be lower than {(gel point TG of the dope) -3} ° C .;
Advancing drying of the flexible film such that the flexible film is hardened to such an extent that the peeled wet film can be conveyed; and
Drying the wet film to form a film; As a solution film forming method comprising:
The said dope is a solution film forming method in which cellulose acylate is dissolved in a solvent. The method of claim 1,
The film forming method of adjusting the temperature of the said flexible membrane by controlling the temperature of the said support body, and advancing drying of the said flexible membrane by sending gas to the said flexible membrane. The method of claim 1,
The solution film-forming method of maintaining the temperature of the said flexible film to the peeling time point so that it may not become higher than {(gel point (TG) of the said dope) +3} degreeC. The method of claim 1,
Further comprising a step of making the pressure of the second space upstream from the roller smaller than the pressure of the first space so that the conveyance path of the wet film facing the roller is convex toward the second space side,
The roller is provided on the opposite side to the support with respect to the conveying path of the wet film, the roller is disposed so as to coincide with the longitudinal direction in the width direction of the flexible surface of the support, the wet film on the circumferential surface of the roller The said flexible film is peeled off by winding and conveying the said wet film, The said 1st space is a space on one film surface peeled from the said support body of the said wet film, The said 2nd space is a space on the other film surface Production method. The method of claim 4, wherein
A solution film for sucking the gas in the second space upstream from the roller by a suction device that sucks gas to depressurize the second space between the roller and the peeling position where the flexible film is peeled off from the support. Way. The method of claim 5, wherein
The said suction device is equipped with the chamber which distinguishes the said 2nd space to be decompressed from an external space, and the solution film forming method which controls the conveyance path of the said wet film toward the said roller by adjusting the pressure in the said chamber. . The method of claim 1,
The solution film-forming method which casts the said dope in the range whose viscosity is 7 Pa * s or more and 9 Pa * s or less to the said support body. The method of claim 7, wherein
The solution film-forming method which controls the said viscosity by adjusting the temperature of the said dope. The method of claim 7, wherein
The said viscosity is a solution film forming method calculated | required based on the pressure loss of the said dope in the said casting die.

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